Fluorescent sign lamp



N. T. GORDON FLUORESCENT SIGN LAMP Filed April 22, 1938 Inventor: Newell T. Gordon,

- is ttorney.

Wutentcd 31, 1939 2.111.110 1. FLUORESCENT SIGN Lazar Newell T. Gordon, Schenectady, N. Y., allignor v w to General Electric Company, a corporation of v 1 r New York Application April 22, 1928, Serial No. 293.546, 4 Claims. (@l. ltd-Ill The present invention comprises an improved electric display lamp in which letters, or other sign characters, are formed of, or outlined by, fiourescent materials which are caused to become 5p", luminous under the influence of an electric discharge.

it is desirable that in such a lamp the discharge itself should have little or no luminosity, and in general should be as inconspicuous as possible so as not to distract attention from the fluorescent characters.

It is also desirable that the discharge should tuire such path in the lamp that the fluorescent characters which are. mounted inside the lamp lliiiwill receive most eflectively radiation from the discharge. In other words, the discharge should not follow some path in the lamp which is unfavorable to the excitation of fluorescence.

In the construction embodying my invention,

iii both of these desired results are obtained by a simple construction. The, novel features or my invention will be set forth by the accompanying cls, and will be described hereinafter in connection with the accompanying drawing.

The drawing shows in Fig. l a side elevation oi'a lamp and auxiliaryapparatus; Fig. 2 is a side elevation of the lamp; Fig. 3 is a cross-section of the lamp of Fig. 1 taken on the line 3-3; and

4 illustrates in longitudinal section a modi- "gfication.

The lamp shown in Fig. 1 comprises a sealed, elongated tubular envelope I which contains a suitable charge of gas, preferably a rare gas, such as argon or krypton, in which an electric discharge will produce but low luminosity. However, the presence of a small amount of mercury vapor is not excluded. I prefer to employ argon at a pressure within the range of about .5 to 2 mm. oi mercury pressure. The envelope is given so a preliminary exhaust by well understood methods, then is charged with gas at desired pressure,

and finally is sealed at! in the usual way. At

' the ends of the'envelope l,'electrode chambers 3, 8' extend at right angles and have located therein electrodes 4, 5. These electrodes are mounted on leading-in conductors 6, I. which are sealed into stems 8; 9 in the usual way. The electrodes t, t are shown as representative either or the cold electrode type, operating with a high voltto age drop, or of the oxide-coated heated electrode type, operating with a low voltage drop. .As well understood, both types are suitable for the purpose of maintaining an electric discharge in an attenuated gea -For examplefelongated cylinmi ders oi nickel or iron, coated with barium oxide,

I may be used as electrodes. The electrodes are supplied with energy by the conductors. lI,-'l2, which are connected to a suitable source-suchas the secondary winding of a transformer H. The

electrode chambers 3, l and the transformer I35 5 are enclosed in a housing I4. J

In the main portion of the envelope, 2. plate i6 is mounted in a longitudinal position, as best indicated in- Figs. 2 and 3. On this plate, which may consist of glass, ceramic, or other suitablemfi material, are placed desired letters or characters oi fluorescent material, indicated at I1, such for example, as zinc silicate, calcium tungstate, cadmium silicate, or borate, or desired mixtures thereof. material may be used. The space adjacent the uncoated side or the plate I! is shut-oil to the discharge by end shields I8, I9, which may consist of metal, such as nickel, or of a suitable ceramic material. These end shields are held on the plate l6 by suitable clips 20. The shield l9 (and through it the plate I8) is anchored by a support 28, which in turn is attached to a sealed-in wire 22.

When a discharge is initiated between the electrodes l, 5, the fluorescent coating (here indicated by the legend "Vapor lamps"), glows brightly by fluorescence, the discharge passing in radiating relation in front or the fluorescent material. In

the absence of the barrier shields l8, IS, the dis- 8o charge would traverse the shortest path through the tube, that is, pass back of the plate l6 where its radiation would not cause fluorescence of the coating i oronly ieeble fluorescence.

As illustrated by the fragmental view of Fig. 4, 86

the barrier for the arc discharge may assume the form of a tubular shield 23 which surrounds the electrode 24 and one side of which is transverse the space backof the plate IS. The electrode 24 in this case extends beyond the side ,ehambero 3, so that the discharge in the absence or the barrier 23 would pass on the uncoated side of the plate I! to a cooperating electrode (not shown). When this construction is used, the

shields l8, I! may be omitted.

In my improved lamps, the electric gas ionization discharge is nearly unnoticeable, particularly when argon is used, and the fluorescent characters stand out in bright relief, compelling attention to the sign.

What I claim as new and desire to secure by Letters Patent ofithmppited States is; I

1. A fluorescent display lamp comprising a sealed elongated container, electrodes spaced apart therein, a charge of attenuated gas therein, 66

Any desired and suitable fluorescent l5.

a longitudinal support thereinhaving fluorescent characters provided thereon, and barrier means located between said electrodes and extending transversely in a path "between said electrodes shielded from said fluorescent characters to increase the lengthoi the discharge path between said electrodes, whereby a' low'iuminosity discharge" between said" electrodes is'guided into fluorescence 'excitihg'relation to said characters. it 2. An electric display" lamp comprising a V, sealed, transparent elongated container; electrodes adjacent opposite ends'ot :said container,

a charge of 'attenuated'gas therein, a plate hitting a surracecoated with fluorescent material locat- F ed in a longitudinal "position in said-"container, and leaving a space between an unc'oated surfaceand a wall of said container and transverse barers in said space for obstructing a low luminosity hage "between said electrodes through said space and to increase the length of the discharge path between said electrodes. I

3. An electric sign lamp comprising a" sealed,

transparent cylindrical containena charge of chamber and transversely extending 'side'cham' -bers,-a charge'of argon gas therein ata pressure of about one-half to two-'millimetersoi mercury, electrodes in v said side chambers, an :elongated plate in said main chamben'a coatinghtflourescent material on one'sid'eionly oi' said plate. =and transverse shields 'mounted :on oppositei'en'ds of said plate extending transversely .theretoJinm positionxbiocking "the space :on the uncoated "side. of said. plateto increasethe-length of the charge path between said-electrodes.- I

t NEWELL T.GORDON. 

